Layers are a powerful feature of Photoshop that enable you to work on one part of an image without disturbing the rest of it. While the concept of layers may seem intimidating at first, you’ll wonder how you ever survived without them once you get the hang of using layers. Figure 1.7 shows a Photoshop document made up of layers.
Figure 1.7. Layered Photoshop document
Figure 1.8. The layers in a layered Photoshop document
The transparent parts of any layer , shown by a checkered grid, allow the layers beneath that layer to show through. You can show and hide each layer in an image by clicking on its corresponding eye icon in the Layers panel, as shown in Figure 1.9.
Figure 1.9. Hiding a layer
T o organize your layers, you can arrange them into layer groups by going to Layer > New > Group….Each layer group displays in the same way as any ungrouped layers on the Layers panel. A layer group is signified by a folder icon. Y ou can collapse or expand layer groups by clicking on the triangle to the left of the folder icon, and nest layer groups within each other by dragging one folder icon into another .
Layer Shortcuts and Tasks
■ Rename layers by double-clicking on the layer name.
■ Change the transparency of a layer by changing its opacity with the Opacity slider , or typing a value into the Opacity box.
■ Duplicate a selected layer by pressing Command-J (Ctrl-J on Windows). You can also duplicate a layer by dragging it while pressing the Option (Alt) key . Or you could type Shift-Option (Shift-Alt) and then hit an arrow key to duplicate the layer and nudge it ten pixels in your desired direction (note that this only works when you have the Move Tool invoked).
■ Select multiple layers by holding down Command (Ctrl) and clicking the layer names. This forms a temporary link between the selected layers that allows you to move them as one unit, delete them all, and so on.
■ You can also link layers together . Select layers by clicking on them while holding down Shift or Command (Shift or Ctrl on Windows). Once you’ve selected all the layers you wish to link, click the Link layers button at the bottom-left of the Layers panel (signified by the chain). Linking layers allows the link relationship to remain even after you select a different layer (unlike the process of simply selecting multiple layers).
To unlink all the layers, select one of the linked layers and go to Layer > Select Linked Layers to select all of them automatically; then go to Layer > Unlink Layers. T o unlink a single layer , select the layer you wish to remove from the link and click the Link layers button at the bottom-left of the Layers panel; the other layers will stay linked. T o temporarily unlink a layer , hold down Shift and click on its corresponding link icon (a red “X” will appear over the link icon). React-ivate the link by holding down Shift and clicking the link icon again.
■ Rearrange layers by dragging the layer above or below other layers. Use the “move down” shortcut Command-[ (Ctrl-[) and the “move up” shortcut Command-] (Ctrl-]) to move selected layers up and down. Command-Shift-[ and Command-Shift-] (Ctrl-Shift-[ and CtrlShift–] on Windows) will bring layers to the very top or very bottom of the stack.
■ Select a layer by using the keyboard shortcuts Option-[ and Option-] (Alt-[ and Alt-] on Windows). These keystrokes let you move up and down through layers in the Layers panel.
■ Create a new layer by pressing Shift-Command-N (Shift-Ctrl-N on Windows). This will bring up the New Layer dialog box. Want to create new layers quickly without having to deal with the dialog box? Simply press Command-Option-Shift-N (Ctrl-Alt-Shift-N)
■ Merge a layer into the one beneath it by pressing Command-E (Ctrl-E). If you’ve selected layers,this shortcut will merge those selected layers together .
Some Photoshop documents grow to have dozens of layers. Even if you’ve diligently named your layers so that they’re easily identifiable, it might be challenging to find the specific layer you want to work on. This is where the top section of the Layers panel comes in and saves the day .
My sunset document only has a few layers, but it has enough to make my point. In Figure 1.10, the top row of the Layers panel in the image on the left shows the search and filtering tools. By default, the filter type is set to Kind, which allows you to filter the different types of layers: image layers, adjustment layers, text layers, shape layers, or smart object layers. In the middle diagram, I’ve selected the Filter for type layers option, and instantaneously , only the text layers of the document are shown! You can imagine how this would simplify finding a layer in a document with a hundred layers.
Figure 1.10. Filtering and searching layers
The right-hand side image of Figure 1.10 reveals that I’ve changed the filter type to Name, enabling me to search for a string of letters across layers. As you explore the other filter types, you’ll find them to be invaluable when navigating documents containing many layers.